The purpose of this project is to study the immune response of laboratory animals to pathogenic fungi. Emphasis is on the investigation of the humoral response as it may be affected by schedule of immunization, to immunizing strain, and the antigenic group. Antibody levels are measured by agglutination and quantitative precipitation using unabsorbed and absorbed antisera. BIBLIOGRAPHIC REFERENCE: Hasenclever, H.f. and Piggott, W.R.: Colonization of soil by Histoplasma capsulatum: II. Effect of bat guano added to an area of reduced colonization. Health Lab. Sci. 13: 203-206, 1976.